What is leptomeningeal myeloma? Is it the same as CNS myeloma? How common is it?
If you look in the literature, there are many definitions of CNS myeloma. I will be talking about a very specific subset, which includes myeloma affecting the brain, affecting the covering of the brain, which is called leptomeningeal disease, which is leptomeningeal myeloma are affecting the CNS which is the fluid covering the brain. There are myeloma that occurs in the in the skull, the cranium, and extend into the brain. Those patients in some studies are going to the CNS myeloma. But really they are not because those patients do very well when they receive radiation or systemic treatment. To diagnose brain myeloma is called it or leptomeningeal myeloma. We need two things. Number one, imaging. And the standard imaging is MRI. And also we need pathology meaning we need to get a CSF or put a needle in the back of the spine to get small amounts of fluids from around the brain to see if there is any plasma cells in it. And if we find plasma cells that would define CNS myeloma. It’s a very rare occurrence in myeloma. We don't see many myeloma with CNS. So meaning that the myeloma cells are, detected on the, cerebral fluids. And we don't see it’s very uncommon complications or sequela. You know, we see more, over the last decade with the introduction of the new agents, patients living longer, but sometimes the myeloma becomes more, refractory escaping. And you can detect, the disease, using a brain MRI. You see the enhancement of the meningeal space, or with the lumbar puncture. So, a lot of time, when you have a patient with, brain metastases, you can see that you have to exclude, that there is no involvement. And also sometimes, large, a lesion in the skull when you do a brain MRI, you can see the erosion. If you want to say the intra cortical erosion of the mass. And so you have to exclude and you, you look in the literature and even the experience of a physician like myself seeing all these patients with myeloma, it's really scars of the cause, as I mentioned earlier, is not very common. Maybe occurring less than 1% of patients with myeloma. So we do have in the literature, you know, some data of using intrathecal chemotherapy and also not all agents that we use for myeloma are, crossing the barrier. So you really have to be cautious on what you choose a systemically for treatment. Is now, as I say, a common complication. So it’s also not a very, easy complication to treat. It’s a type of CNS myeloma because you have, the cells in the myeloma cells circulating in the, in the cerebral fluid. So when you do a lumbar puncture, you can detect the myeloma cells. Again, we don't see a lot of the, patients presenting it but it’s when the myeloma, it's crossing the barrier. And so it's on the fluid circulating around, and, and as I mentioned earlier, very rare. We don't routinely perform a lumbar puncture, like, there are some patients with leukemia, particularly, acute lymphocytic leukemia or type of lymphoma, CNS lymphoma. Presenting with these the myeloma is very rare. I’ve been doing in myeloma for many years, 20 plus. And I really didn't see a lot of patients with CNS involvement. Sometimes you have an isolated brain lesion. It happened in, a few brain mats, but not necessarily the meningeal. The CNS involvement.